This invention relates generally to a method for determining the composition and characteristics of the individual materials within a multi-material object, and, more specifically, to a method of analyzing the electrical network representation of the multi-material object.
Multiphase flow is an example of a multi-material object in which at least two materials or phases are flowing together inside a pipe or a conduit. Multiphase flow processes are important to a variety of industries including, for example, petroleum, pharmaceutical, food, and chemical industries. There is a need for direct knowledge of the internal flow characteristics in these types of multiphase flow processes to enable improved design and increased operational efficiency of existing and new processing equipment. Characteristics used to predict performance of multiphase processes may include, for example, spatial distribution of the phases (spatial volumetric phase fractions), flow regime, interfacial area, and absolute and relative velocities between the phases or materials. Knowing the spatial distribution of the materials is particularly useful because non-uniform distribution of the materials tends to reduce the interfacial area between materials available for chemical reaction or conversion and may result in recirculating flows creating spatially non-uniform reaction zones or concentrations. Further, the volumetric phase fraction and velocity are important parameters that enable proper and timely control of multiphase flows.
Electrical-impedance tomography (EIT) is a minimally invasive measurement technique that can be used to quantitatively map material distributions within multi-material objects. In EIT, a map of the electrical conductivity and permittivity is used to infer the distribution of different materials within a multi-material object. Different current patterns or voltage patterns are applied to the object through electrodes surrounding the object, and the corresponding voltages or currents are measured. Based on the current-voltage relations, an internal impedance or internal admittance distribution is determined.
Image reconstruction based on the calculated impedance distribution using various image processing algorithms is one method by which distribution of different materials within the multi-material object is determined. However, image-processing algorithms are often too time-consuming and computationally intensive. They also ignore many qualitative aspects of the problem such as spatial symmetry or asymmetry.
Therefore, it is desirable to determine a method and a system that will address the foregoing issues.